I mean, a better example of Superman being unreasonably angry would be in the Captain Marvel episode where he acts super paranoid about Luthor and is kind of a dick to Captain Marvel the entire time. I still liked it, because it was in the middle of the Cadmus arc where everyone was under stress and in this case it was especially personal for Superman, but it's a much better example than Superman raging at a literal living embodiment of evil who murdered a friend of his and is so casual about it he doesn't even remember the dude's name.